I bought a GeForce promotion AC3...

Wait, to clairify, I mean, if I put the code in the promo code box to see if it works, but not check out the game, will that activate the code? Wondering since I saw some other users saying you can check the code in Uplay.

If it promocode - enter at geforce site and get key with download link.

And after trading give key and link.

You enter the code at the Nvidia site and then they send you an email with a key to use at the Ubi store. It isn't tied to your account at that point. I don't know if it would be if you used it at the Ubi store. The email will look like this:

"YOU'VE GEARED UP FOR THE GAME. NOW GET YOUR FREE ASSASSIN'S CREED III<br>
Redeem your UbiShop code below to receive your digital download for the PC Version of Assassin's Creed III.<br>
Your game code: (key is here)<br>
Do not share this key. Otherwise, you may not be able to play.<br>
Visit shop.ubi.com to redeem your code and download your free game."<br>